N2 O在Mg－Fe复合氧化物上的催化分解

摘要

A series of Mgx Fe1-x Fe2 O4 spinel oxides were prepared and characterized by means of nitrogen physisorption, X-ray diffraction ( XRD ) and temperature-programmed reduction of hydrogen ( H2-TPR ) . The effect of composition, calcination temperature, and potassium doping on the catalytic activity of the Mg-Fe mixed oxides in N2 O decomposition was investigated.The results indicated that the Mg0.6 Fe0.4 Fe2 O4 catalyst calcined at 500℃exhibits highest activity in N2 O decomposition.Unexpectedly, the catalyst activity is depressed by the addition of potassium, as the potassium doping may inhibit the reduction of surface iron oxides and reduce the surface area of K-modified catalysts.Long-term tests at 500℃for 10 h also illustrate that Mg0.6 Fe0.4 Fe2 O4 is superior to FeOx catalyst eti her in the oxygen-alone or in the oxygen-steam concomi tant atmosphere.%用共沉淀法制备了一组Mg－Fe复合氧化物催化剂，用于N2 O催化分解，考察了催化剂组成、焙烧温度、负载助剂钾等参数对其催化活性的影响。采用N2物理吸附、X射线衍射、H2－程序升温还原等技术对催化剂进行了结构表征。结果表明，500℃焙烧的Mg0．6 Fe0．4 Fe2 O4催化剂对于N2 O分解反应有较高活性，而K改性的催化剂活性均有所降低，且K的负载量越高，改性催化剂的活性越低，这是由于负载的K粒子抑制了表面铁物种的还原，降低了催化剂的比表面积。在有氧无水、水氧共存条件下连续反应10 h，Mg0．6 Fe0．4 Fe2 O4的催化活性和稳定性均显著高于FeOx催化剂。